1. Field of the Invention
In the last decade a large variety of individual plants from numerous accessions of naturally occurring populations have been evaluated for salt and boron tolerance and accumulation of selenium. These include; mustard and canola (Banuelos et al., 1998), poplar trees (Shannon et al., 1999), broccoli (Banuelos et al., 2003), birdsfoot trefoil (Steiner and Banuelos, 2003), and Indian Fig Opuntia (Banuelos and Lin, 2010) that were tested under typical poor quality soil conditions present in agricultural drainage sediment and in the Westside of the central valley. The identification of new crops is a prerequisite for the agricultural use of over 500,000 acres of fallowed and drought-stricken hypersalinized soils in the relevant region of California. Importantly, plants that are salt and boron tolerant and require minimum water, are top priority for growers in this part of California.
2. Description of the Relevant Art
Opuntia ficus-indica cultivar selections have been previously identified and described (Felker et al., 2005; Parish and Felker, 1997). Four U.S. Plant Patents were issued for newly developed cactus pear varieties (U.S. Plant Pat. No. 21,760 P2, U.S. Plant Pat. No. 21,834 P2, U.S. Plant Pat. No. 21,964 P2, and U.S. Plant Pat. No. 22,077 P2). Opuntia ficus-indica is a species of cactus that produces edible fruit and cladodes. The fruits can have large distinct surface spines, small hairy barbed glochids, or be mostly spineless. They are grown in arid parts of the world, such as Central America, South America, Spain, Italy, Israel and South Africa (Parish and Felker, 1997).
Opuntia ficus-indica fruit and the succulent vegetative pads or cladodes (modified stems) have chemotherapeutic medicinal properties that when consumed, can reportedly help improve human immune and nervous systems, reduce oxidative stress through scavenging free radicals, treat gastritis, reduce hyperglycemia, reduce atherosclerosis, inhibit diabetes and prostatic hypertrophy (enlarged prostate) (reviewed by Feugang et al., 2006). Uniquely, Opuntia ficus-indica fruit extracts are also reported to inhibit the growth of human ovarian, cervical and bladder cancer cell lines, and reduce the high rate of tumor formation in carcinogen-stressed nude mice (Zou et al., 2005).
The medicinal chemotherapeutic effects are at least in part a result of the antioxidant phytochemicals or pigments concentrated in Opuntia ficus-indica fruit and these compounds may help provide protection against multiple chronic human diseases. Polyphenolic flavonoids (quercetin, kaempferol and isorhamnetin), various carotenoids and the betalains (betanin and indicaxanthin) in the fruit are previously reported to have a high rate of antioxidant activity. Additionally, the fruit are rich in ascorbic acid and contain high levels of amino acids, especially proline, taurine and serine (Feugang et al., 2006). Cladodes from the Opuntia ficus-indica plant are naturally-enriched in niacin (B3), amino acids and fiber, and are reported to prevent excess blood sugar conversion into fat and lower total cholesterol, triglyceride and low density lipid levels.
Moreover, they contain elevated concentrations of vitamins A, B, and C. Also, Opuntia ficus-indica contains the following minerals: calcium, magnesium, sodium, potassium, and iron (Feugang et al., 2006). And Opuntia ficus-indica contains the following fibers: lignin, cellulose, hemicelluloses, pectin, mucilage's and gum form (Feugang et al., 2006). In addition, Opuntia ficus-indica contains 17 amino acids (Feugang et al., 2006). Organo-seleno forms are generally considered more bioavailable to antioxidant enzymes, i.e., selenoglutathione peroxidase (Stadtman, 1980), are easier to metabolize by humans, and are reported to have greater anticarcinogenic activity (Ip & Ganther, 1992; Clark et al., 1996).